why do girls do this

why do girls make other girls lifes miserable over stupid rumers and misunderstandings in the movie they were SO MEAN TO HER over a stupid boy and they whole thing was a big missunderstanding they drove this girls to cut her hair even try to comit suiside i mean THIS HAS TO STOP i am not saying all girls do this but but there are girls who do and it is down right terrible and more movies like this need to be made to show these girls how terrible it is in my oppinion at school it should be required in an assembly all girls watch this movie maybe it will make some think about what they have done to other girls around them and change their ways if anyone agrees with me respond